Investigators hunting for the cause of the crash of an Ethiopian Airlines plane that killed all 157 people on board have begun studying the cockpit voice recorder, France`s BEA air accident investigation agency said on Saturday.

Experts say it is too soon to know what brought down the Boeing 737 MAX 8 on March 10, but aviation authorities worldwide have grounded Boeing`s 737 MAXs, as concerns over the plane caused the company`s share price to tumble.

A spokesman for the BEA agency said downloading the data from the recorder retrieved from wreckage was expected to take four to five hours. The BEA also issued a photo showing the recorder intact but dented by the impact of the plane`s crash into a field minutes after take-off from Addis Ababa.

"We are waiting for the results. We are making all the necessary efforts to identify the cause of the accident," Ethiopian Minister of Transport Dagmawit Moges told reporters in Addis Ababa.

"This kind of investigation needs considerable amount of time to reach concrete conclusions".

The Ethiopian carrier said DNA testing of the remains of the people on board flight 302 may take up to six months, and it offered bereaved families charred earth from the plane crash site to bury. Passengers from more than 30 nations were aboard.

Dagmawit said temporary death certificate had been given, and a final one would be issued in two weeks time. Collection of DNA samples from relatives had begun.

Victim identification would be done to scientific international standards, and internationally-recognised organisations such as Interpol were going to be involved in the process, she said.

As families wait for the results from the investigation, Ethiopian Airlines is planning to hold a service on Sunday in Addis Ababa, at the Kidist Selassie, or Holy Trinity Cathedral, where many of the country`s past rulers are buried beneath its pink stone spires.EARTH FROM THE CRASH SITE

"We were told by the company that we will be given a kilo (of earth) each for burial at Selassie Church for a funeral they will organise," said one family member who asked not to be named.

Papers given to the families at the Skylight Hotel on Saturday said death certificates would be issued within two weeks, and an initial payment made to cover immediate expenses.

The return of remains - most of which are charred and fragmented - would take up to six months, the papers said, but in the meantime earth from the crash site would be given.

Abdulmajid Sheriff, a Kenyan whose Yemeni brother-in-law died, said the family had already held a service.

"We are Muslims we didn`t care about that (earth). We did yesterday our prayers at the mosque and that is all for us."

Around 100 relatives, including the brother and father of pilot Yared Getachew, gathered at a memorial for the victims at the Kenyan embassy.

"His dream was to be a pilot," said Meno Getachew Tessema, 39, Yared`s brother. "He was diligent, hardworking, he had a consistent work ethic. I would like to emphasize his record and that he was a rising star at Ethiopian Airlines."

Flight data has already indicated some similarities with a crash by the same model of plane during a Lion Air flight in October. All 189 people onboard were killed. Both planes crashed within minutes of take off after pilots reported problems.

The grounding of the 737 MAX jets has had no immediate financial impact on airlines using the planes, but it will get painful for the industry the longer they do not fly, companies and analysts said on Friday.

Boeing plans to release upgraded software for the 737 MAX in a week to 10 days, sources familiar with the matter said.

The U.S. planemaker has been working on a software upgrade for an anti-stall system and pilot displays on its fastest-selling jetliner in the wake of the deadly Lion Air crash.

(This article has not been edited by Zeebiz editorial team and is auto-generated from an agency feed.)